Messi inspired a devastating second-half performance from Barcelona, scoring twice and creating another for Luis Suarez as Ernesto Valverde's La Liga leaders stormed to a 5-0 win at Estadio Benito Villamarin.
The result extended Barca's advantage at the summit over Atletico Madrid to 11 points and Real Madrid youth graduate Adan was left in awe, having mistakenly felt his team-mates might have had Messi under control.
"It's spectacular. In the first half he had not appeared. He seemed to be walking," the 30-year-old told Cadena Ser.
"But he takes four balls to score two goals and give two assists. He makes this sport better."
Betis vice president Lorenzo Serra Ferrer also felt it had been a privilege to witness Messi at his brilliant best.
"Messi deserves that because it is a show, what he has done in the second half," he said.
"Not only in attack but claiming balls in their own half of the field.
"His humility and ability make him bigger and the public of the Villamarin has been able to appreciate the extraordinary player that is Leo Messi."